The invention relates to dental materials which, in addition to a filler and a polymerizable matrix, contain a component which contracts during thermal treatment.
Dental materials based on plastics contain in general one or more fillers in addition to a polymerizable matrix. The fillers serve to reduce the polymerization shrinkage and to improve the mechanical properties of the cured materials. Fibre composites contain fibrous fillers such as fibre mats or fibre bundles, which are impregnated with the organic polymer matrix. For reasons of stability, it is advantageous to select the filler content as high as possible. This has however the disadvantage that the rigidity of the uncured material is increased and thus its shaping made difficult.
WO95/08300 discloses a process for preparing dental restorations from fibre composites in which fibre mats saturated with polymer matrix are applied to a tooth cast, matched to the cast in a thermoforming process and then cured. The frame obtained in this way can be further processed e.g. by applying facing material.
EP 0 872 218 A2 discloses a process for preparing fibre-reinforced dental restorations, in which the fibre content of the uncured starting material is increased during deep-drawing by expressing excess matrix material. The process necessitates the use of specially designed moulds.
The known deep-drawing processes have the disadvantage that the compaction forces do not act homogenously on the material from all sides simultaneously and no uniform compaction of the materials is achieved.
The object of the invention is the provision of dental material which can be compacted uniformly without special auxiliary agents.